JP7843862B2 - Battery pack - Google Patents

Description

This application claims priority to the Chinese patent application No. 202211598515.7, filed with the China National Intellectual Property Office on December 14, 2022, and the entire contents of the said application are incorporated into this application by reference.

This application relates to the technical field of battery packs, and more particularly to battery packs.

In recent years, the demand for lighter automobiles has been increasing, and in the field of new energy vehicles in particular, driving range has always been a bottleneck limiting performance development. In related technologies, extending driving range typically involves increasing the energy density of the battery pack or increasing the number of modules, from the perspective of increasing the total energy of the battery. Furthermore, to improve the space utilization rate of electric vehicles, a two-layer module structure is usually used. The emergence of a two-layer module structure allows for effective utilization of the envelope space, thereby improving the driving range of electric vehicles.

In the design process of related dual-layer module battery packs, sealing is difficult, making it challenging to design dedicated exhaust and pressure relief passages. Because dual-layer module battery packs lack these dedicated passages, if thermal runaway occurs in a cell on the module, a large amount of gas and associated flames are instantly released into the cell. Since there are no directional exhaust passages to guide these gases and flames, they spread randomly within the battery pack, easily igniting other components. This can cause thermal runaway in other cells operating normally, leading to the spread of thermal runaway and increasing the risk of fire or explosion. There is room for improvement in this area.

In one embodiment, this application provides a battery pack that prevents the spread of thermal runaway.

The battery pack is
A battery module comprising a pair of battery assemblies stacked and arranged along the height direction,
Each battery assembly includes a support tray and a cell group, the support tray has multiple through holes extending along its height, multiple pressure relief valves for multiple single cells within the cell group are arranged one-to-one in the multiple through holes, a pair of pressure relief valves for cell groups arranged along the height direction are arranged opposite each other, and the support tray is further provided with multiple pressure relief holes, the battery module,
A module bracket is provided between a pair of support trays arranged along the height direction and has a first pressure relief passage, wherein a pressure relief cavity is provided between the pair of support trays arranged along the height direction, and the through hole, the pressure relief cavity, the first pressure relief passage, and the pressure relief hole are in communication with each other.
The present invention includes a housing in which a battery module is provided, a third pressure relief passage is provided in the housing, and the third pressure relief passage and the pressure relief hole are in communication with each other.

In one embodiment, each support tray includes a tray body with mounting grooves and a tray extension provided on the periphery of the tray body, and each tray body is provided with a plurality of through holes extending through it in the height direction.
A pressure relief cavity is provided between a pair of tray bodies arranged along the height direction, and the module bracket is provided between a pair of tray extensions arranged along the height direction.

In one embodiment, both the tray extension and the module bracket are rectangular ring-shaped.

In one embodiment,
The structure further includes a fire-resistant plate placed between a pair of tray bodies arranged along the height direction, with the through-holes of the upper tray body and the lower tray body separated by the fire-resistant plate.

In one embodiment, side beams and a plurality of first crossbeams are provided inside the housing, the side beams are combined to form a frame structure, and a third pressure relief passage is provided inside the side beams.
Multiple first crossbeams are provided inside the frame structure and connected to the side beams, and the multiple first crossbeams divide the frame structure into multiple regions, each of which is provided with a battery module.

In one embodiment, the first crossbeam is provided with a second pressure relief passage, and the first pressure relief passage, the pressure relief hole, the second pressure relief passage, and the third pressure relief passage are in communication with each other.

In one embodiment, a pair of support trays arranged symmetrically along the height direction are provided, and the lower tray extension is equipped with multiple pressure relief holes, with the pressure relief holes, a second pressure relief passage, and a third pressure relief passage communicating with each other.

In one embodiment, an explosion-proof valve is provided on the side beam, and the explosion-proof valve is connected to a third pressure relief passage.

In one embodiment, a module bracket and a pair of tray extensions arranged along the height direction are connected by a locking mechanism to fasten the fireproof plate.

In summary, the battery pack provided by the embodiments of this application has the following beneficial effects:

In actual applications, in the two-layer battery assembly of the battery pack embodiment of this application, each single cell of the battery assembly is a cylindrical cell, and the pressure relief valve of the cylindrical cell is located at the bottom of the cell itself. Therefore, the two-layer battery assembly has a mounting structure in which the bottoms of the single cells are arranged opposite each other. When the battery overheats and becomes uncontrollable, the generated gas and flame concentrate in a pressure relief cavity formed between a pair of support trays arranged vertically through through holes. Next, the generated gas and flame flow into a first pressure relief passage of the module bracket, then into the pressure relief holes of the support trays, and finally into a third pressure relief passage of the housing. These gases and flames are guided through the third pressure relief passage, thereby effectively preventing the random spread of gas and flame within the battery pack, effectively preventing the diffusion of thermal runaway, and preventing more serious fire or explosion.

Additional aspects and advantages of this application are, in part, described below, and in part will become apparent from this description or be understood through the practice of this application.

This is a schematic diagram of the structure of the battery pack in the embodiment of this application. This is a schematic diagram of the internal structure of the battery pack in the embodiment of this application. This is a magnified view of part A in Figure 2. This is another schematic diagram of the internal structure of the battery pack in the embodiment of this application. This is a schematic diagram of the structure of the support tray in an embodiment of this application. This is a schematic diagram of the structure of the module bracket in the embodiment of this application. This is a schematic diagram showing the disassembled state of the battery pack in the embodiment of this application.

Furthermore, in the description of this application, the orientations or positional relationships indicated by terms such as "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "top," "bottom," "inside," and "outside" are based on the orientations or positional relationships shown in the drawings and are merely for the purpose of facilitating and simplifying the description of this application. They do not suggest or imply that the devices or elements mentioned have a specific orientation or must be constructed and operated in a specific orientation, and therefore cannot be interpreted as limiting this application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application pertains. The terms used herein in this description are for the sole purpose of describing specific embodiments and are not intended to limit this application.

The battery pack and power consumption device according to embodiments of this application will be described below with reference to Figures 1 to 6. Several embodiments of this application will be described in detail below, in conjunction with the accompanying drawings. The following embodiments and features can be combined with each other, as long as they do not contradict each other.

In recent years, the demand for lighter automobiles has been increasing, and in the field of new energy vehicles in particular, driving range has always been a bottleneck limiting performance development. In related technologies, extending driving range typically involves increasing the energy density of the battery pack or increasing the number of modules, from the perspective of increasing the total energy of the battery. Furthermore, to improve the space utilization rate of electric vehicles, a two-layer module structure is usually used. The emergence of a two-layer module structure allows for effective utilization of the envelope space, thereby improving the driving range of electric vehicles.

In the design process of related dual-layer module battery packs, sealing is difficult, making it challenging to design dedicated exhaust and pressure relief passages. Because dual-layer module battery packs lack these dedicated passages, if thermal runaway occurs in a cell on the module, a large amount of gas and associated flames are instantly released into the cell. Since there are no directional exhaust passages to guide these gases and flames, they spread randomly within the battery pack, easily igniting other components. This can cause thermal runaway in other cells operating normally, leading to the spread of thermal runaway and increasing the risk of fire or explosion. There is room for improvement in this area.

In view of the above, the battery pack in the embodiment of this application is provided with a dedicated exhaust and pressure relief structure in the two-layer module that guides these gases and flames in a specific direction in the event of thermal runaway, thereby preventing the spread of thermal runaway.

Specifically, please refer to Figures 1 to 6. The battery pack in this embodiment includes a battery module, a module bracket 2, and a housing 6.

In one embodiment, the battery module includes a pair of battery assemblies 1 stacked vertically along the height direction, each of which includes a support tray 11 and a cell group 12. The support tray 11 has a plurality of through holes 111 extending through it along its height direction, and pressure relief valves for a plurality of single cells within the cell group 12 are arranged in a one-to-one correspondence with the plurality of through holes 111. The pressure relief valves for the pair of cell groups 12 arranged along the height direction are arranged opposite each other, and the support tray 11 is further provided with a plurality of pressure relief holes 112. The module bracket 2 is positioned between the pair of support trays 11 arranged along the height direction, and the module bracket 2 is provided with a first pressure relief passage 21. A pressure relief cavity 3 is provided between the pair of support trays 11 arranged along the height direction, and the through holes 111, the pressure relief cavity 3, the first pressure relief passage 21, and the pressure relief holes 112 are in communication with each other. The battery module is housed within the housing 6, which is provided with a third pressure relief passage 71. The third pressure relief passage 71 and the pressure relief hole 112 are in communication.

In actual applications, in the two-layer battery assembly 1 of the battery pack embodiment of this application, the single cells of the battery assembly 1 are cylindrical cells, and the pressure relief valve of the cylindrical cell is located at the bottom of the cell itself. Therefore, the two-layer battery assembly 1 has a mounting structure in which the bottoms of the single cells are arranged facing each other. When the battery overheats and becomes uncontrollable, the generated gas and flame concentrate in the pressure relief cavity 3 formed between a pair of support trays 11 arranged vertically through the through-hole 111. Next, the generated gas and flame flow into the first pressure relief passage 21 of the module bracket 2, then into the pressure relief holes 112 of the support trays 11, and finally into the third pressure relief passage 71 of the housing 6. These gases and flames are guided through the third pressure relief passage 71, thereby effectively preventing the gases and flames from spreading randomly within the battery pack, effectively preventing the spread of thermal runaway, and preventing more serious fires or explosions.

Further applications reveal that a two-layer module configuration within the battery pack can effectively improve the driving range of electric vehicles, but this increases the thickness of the battery pack. Therefore, to reduce the overall thickness of the battery pack, the structure of the support tray 11 is improved, and the installation position of the module bracket 2 is adjusted accordingly. This reduces the thickness of the battery pack to a certain extent, achieving miniaturization and weight reduction.

Specifically, please refer to Figures 1 to 6. In the battery pack of this embodiment, each support tray 11 includes a tray body 113 with mounting grooves and a tray extension 114 provided on the periphery of the tray body 113. Each tray body 113 has a plurality of through holes 111 extending through it in the height direction. A pressure relief cavity 3 is provided between a pair of tray bodies 113 arranged in the height direction, and the module bracket 2 is provided between a pair of tray extensions 114 arranged in the height direction.

In actual applications, the battery module of the battery pack in the embodiment of this application is provided with a pair of support trays 11. Since the support trays 11 include a tray body 113 with mounting grooves, the tray body 113 itself has a certain height, thereby creating a mounting gap between the pair of tray extensions 114 for attaching the module bracket 2. Therefore, the cell group 12 is mounted corresponding to the mounting grooves of the tray body 113, the module bracket 2 is mounted corresponding to the tray extensions 114, and the cell group 12 is provided correspondingly within the module bracket 2. Consequently, the heights of the cell group 12 and the module bracket 2 partially overlap, resulting in a more compact structure. This allows for a certain degree of reduction in the thickness of the battery pack, achieving miniaturization and weight reduction.

As can be seen from the above, when the battery overheats and becomes uncontrollable, the generated gas and flame concentrate in the pressure relief cavity 3. Next, the generated gas and flame flow towards the edge of the support tray 11, into the first pressure relief passage 21 of the module bracket 2, further into the pressure relief hole 112 of the support tray 11, and finally into the third pressure relief passage 71 of the housing 6. These gases and flames are guided through the third pressure relief passage 71, thereby effectively preventing the random spread of gas and flame within the battery pack, effectively preventing the spread of thermal runaway, and preventing more serious fire or explosion.

Existing battery packs are typically manufactured in a square case shape. To accommodate this square case shape, the battery pack, tray extension 114, and module bracket 2 in the embodiments of the present invention are all rectangular ring-shaped.

Of course, in other embodiments, the tray extension 114 and the module bracket 2 may be circular.

Further applications revealed that, due to the two-layer module configuration of this battery pack, if a single cell in one layer of the cell group 12 experiences thermal runaway, the generated gas and flames are ejected towards the bottom of a single cell in the opposing cell group 12, causing further thermal runaway. Therefore, to prevent the generated gas and flames from being ejected to the bottom of a single cell in the opposing module and causing thermal runaway, this battery pack is equipped with a fire-resistant plate 5 that prevents the diffusion of thermal runaway between the two-layer modules by blocking it.

Specifically, please refer to Figures 1 to 6. The battery pack in this embodiment further includes a fire-resistant plate 5, which is positioned between a pair of tray bodies 113 arranged in the height direction. The through-hole 111 of the upper tray body 113 and the through-hole 111 of the lower tray body 113 are separated by the fire-resistant plate 5.

In actual applications, if a single cell in the cell group 12 of one layer of the battery pack in the embodiment of this application experiences thermal runaway, the generated gas and flame will be ejected towards the fireproof plate 5, flow along the fireproof plate 5 towards the edge of the support tray 11, then flow into the first pressure relief passage 21 of the module bracket 2, further flow into the pressure relief hole 112 of the support tray 11, and finally flow into the third pressure relief passage 71 of the housing 6. These gases and flames are guided through the third pressure relief passage 71, effectively preventing them from spreading randomly within the battery pack, effectively preventing the diffusion of thermal runaway, and thus preventing more serious fires or explosions. Furthermore, it effectively prevents the generated gases and flames from ejecting to the bottom of a single cell in an opposing module, causing thermal runaway, thus preventing the diffusion of thermal runaway between two-layer modules.

The fire-resistant board 5 may be a high-temperature resistant mica board, for example, one that can be manufactured by bonding, heating, and pressurizing mica paper and an organic silicone adhesive. The mica content is approximately 90%, and the organic silicone adhesive content is 10%.

Further applications have shown that to increase the battery capacity of a battery pack, it is common practice to incorporate multiple battery modules within the pack. To enable these multiple battery modules to efficiently dissipate gases and flames generated during thermal runaway, the structure of the housing 6 in this battery pack has been improved.

Specifically, please refer to Figures 1 to 6. In the battery pack of this embodiment, the housing 6 is provided with side beams 7 and a plurality of first crossbeams 4. The side beams 7 are combined to form a frame structure, and a third pressure relief passage 71 is provided within the side beams 7. The plurality of first crossbeams 4 are provided inside the frame structure and connected to the side beams 7. The plurality of first crossbeams 4 divide the frame structure into multiple regions, and a battery module is provided in each region.

In other embodiments, the first crossbeam 4 is provided with a second pressure relief passage 41, and the first pressure relief passage 21, the pressure relief hole 112, the second pressure relief passage 41, and the third pressure relief passage 71 are in communication with each other.

In actual applications, the multiple battery modules and multiple first crossbeams 4 of the battery pack in the embodiment of this application are arranged alternately with spacing between them, so that one battery module is positioned between two first crossbeams 4. When the battery overheats and becomes uncontrollable, the generated gas and flame concentrate in the pressure relief cavity 3 formed between a pair of support trays 11 arranged vertically through the through-holes 111. Next, the generated gas and flame flow into the first pressure relief passage 21 of the module bracket 2, then into the pressure relief holes 112 of the support trays 11, and then first into the second pressure relief passage 41 of the first crossbeams 4, and then into the third pressure relief passage 71 of the housing 6. These gases and flames are guided through the third pressure relief passage 71, thereby effectively preventing the gas and flame from spreading randomly within the battery pack, effectively preventing the spread of thermal runaway, and preventing more serious fires or explosions.

Furthermore, from a positional perspective, the gas and flame generated by the battery module flow to the first crossbeams 4 on both sides, and are then guided through the second pressure relief passages 41. This effectively prevents the gas and flame from spreading randomly within the battery pack, effectively preventing the spread of thermal runaway and thus preventing more serious fires or explosions.

The structure for guiding the flow of the generated gas and flame can be specifically described in Figures 1 to 6. The side beam 7 is provided with an exhaust port, which communicates with the outside of the housing and the third pressure relief passage 71. The exhaust port is sealed by an explosion-proof valve 72, which communicates with the third pressure relief passage 71. The side beam 7 may specifically be concave in shape.

In actual applications, if thermal runaway occurs in the battery module, the generated gas and flames flow into the second pressure relief passage 41 within the first crossbeam 4, then into the third pressure relief passage 71 in the side beam 7, and finally into the explosion-proof valve 72. The explosion-proof valve 72 automatically opens to release the pressure, preventing the battery pack 100 from exploding.

In a further application, a fire-resistant plate 5 is provided between a pair of tray bodies 113 arranged along the height direction. When thermal runaway occurs, the generated gas and flames are ejected towards the fire-resistant plate 5. Therefore, it was found that the fire-resistant plate 5 needs to be fixed to prevent uneven ejection during thermal runaway. This battery pack secures the fire-resistant plate 5 by tightening it with a clamping structure.

Specifically, please refer to Figures 1 to 6. In the battery pack of this embodiment, the module bracket 2 and a pair of tray extensions 114 arranged along the height direction are connected by a locking portion 8 to fasten the fireproof plate 5.

In practical applications, this battery pack secures a pair of tray extensions 114 to the module bracket 2 via locking parts 8, and further fastens the fireproof plate 5 via a pair of tray bodies 113, thereby securing the fireproof plate 5 and preventing uneven ejection during thermal runaway. Here, the locking parts 8 may specifically be bolts or screws.

The embodiments of this application disclose not only battery packs but also power consumption devices including battery packs. Power consumption devices may include, but are not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric bicycles, electric vehicles, ships, and spacecraft. Electric toys may include stationary or mobile electric toys such as game consoles, electric vehicle toys, electric boat toys, and electric airplane toys, and spacecraft may include airplanes, rockets, space shuttles, and spacecraft. Power tools include power tools for metal cutting, polishing, assembly, and railway applications, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers.

1 - Battery assembly, 11 - Support tray, 111 - Through hole, 112 - Pressure relief hole, 113 - Tray body, 114 - Tray extension, 12 - Cell group, 2 - Module bracket, 21 - First pressure relief passage, 3 - Pressure relief cavity, 4 - First cross beam, 41 - Second pressure relief passage, 5 - Fireproof plate, 6 - Housing, 7 - Side beam, 71 - Third pressure relief passage, 72 - Explosion-proof valve, 8 - Locking part

Claims (10)

It is a battery pack,
A battery module comprising a pair of battery assemblies (1) arranged in a stack along the height direction,
Each of the battery assemblies (1) includes a support tray (11) and a cell group (12), each of the support trays (11) includes a tray body (113) having mounting grooves and a tray extension (114) provided on the periphery of the tray body (113), the tray body (113) of the support tray (11) has a plurality of through holes (111) extending through it along its height direction, pressure relief valves for a plurality of single cells in the cell group (12) are arranged one-to-one in the plurality of through holes (111), a pair of pressure relief valves for the cell group (12) arranged along the height direction are arranged opposite each other, the pair of support trays (11) arranged along the height direction are arranged symmetrically, and the tray extension (114) of the lower support tray (11) is further provided with a plurality of pressure relief holes (112), and
A module bracket (2) is positioned between a pair of support trays (11) arranged along the height direction and is provided with a first pressure relief passage (21), wherein a pressure relief cavity (3) is provided between the pair of support trays (11) arranged along the height direction, and the through hole (111), the pressure relief cavity (3), the first pressure relief passage (21), and the pressure relief hole (112) are in communication with each other.
A battery pack comprising a housing (6), wherein the battery module is provided inside the housing (6), the housing (6) is provided with a third pressure relief passage (71), and the third pressure relief passage (71) and the pressure relief hole (112) are in communication with each other. The battery pack according to claim 1, wherein the pressure relief cavity (3) is provided between a pair of tray bodies (113) arranged along the height direction, and the module bracket (2) is provided between a pair of tray extensions (114) arranged along the height direction. The battery pack according to claim 2, wherein both the tray extension portion (114) and the module bracket (2) are rectangular ring-shaped. The battery pack according to claim 2, further comprising a fire-resistant plate (5) provided between a pair of tray bodies (113) arranged along the height direction, wherein the through-hole (111) of the upper tray body (113) and the through-hole (111) of the lower tray body (113) are separated by the fire-resistant plate (5). The battery pack according to claim 4, wherein the fire-resistant plate (5) is a mica plate. The housing (6) is provided with side beams (7) and a plurality of first crossbeams (4), the side beams (7) are combined to form a frame structure, and the third pressure relief passage (71) is provided within the side beams (7).
The battery pack according to any one of claims 2 to 5, wherein the plurality of first crossbeams (4) are provided inside the frame structure and connected to the side beams (7), and the plurality of first crossbeams (4) divide the frame structure into a plurality of regions, each of which is provided with the battery module. The battery pack according to claim 6, wherein the first crossbeam (4) is provided with a second pressure relief passage (41), and the first pressure relief passage (21), the pressure relief hole (112), the second pressure relief passage (41), and the third pressure relief passage (71) are in communication with each other. The battery pack according to claim 7, wherein the pressure relief hole (112), the second pressure relief passage (41), and the third pressure relief passage (71) are in communication with each other. The battery pack according to claim 6, wherein the side beam (7) is provided with an explosion-proof valve (72), and the explosion-proof valve (72) is in communication with the third pressure relief passage (71). The battery pack according to claim 4 or 5, wherein the module bracket (2) and a pair of tray extensions (114) arranged along the height direction are connected by a locking portion (8) to tighten the fireproof plate (5).